| 摘要 |
PURPOSE:To reduce the cost of an equipment by checking the quality and function of a magnetic medium with a simple circuit of a comparator and the like without use of costly parts such as counter. CONSTITUTION:An all one pattern is written into a magnetic medium 1 on a specific writing condition and at a specific cycle with the operation of a writing amplifier 3 and a reading/writing head 4 by a writing-in control circuit 2. The all one pattern simultaneously written is read with said head 4 and a reading amplifier 5 is read out and transferred to a testing section 6, where a reading signal a is compared with the maximum reference voltage VR.MAX and a minimum reference voltage VR.MIN by means of comparators 61 and 62. The output signal b of the comparator 61 is directly fed to a quality discriminating circuit 66 while the output signal c of the comparator 62 thereto by way of a frequency comparator circuit 63. The comparator circuit 63 monitors the cycle of pulses of the output signal c of the comparator 62 and transmits an output signal e of a H level when no pulse is received within a fixed cycle. |
